You could argue the turning point of the 2012 U.S. Open—which starts today—already happened. Well, three turning points, actually.

1. Rafael Nadal withdraws with a knee injury. People who follow tennis will tell you they've seen this coming since before Nadal wore sleeves. He plays too hard to hold up for two weeks on the hard courts of Queens, year after grueling year. The day Nadal announced his withdrawal via—what else?—Twitter, Patrick McEnroe, one of ESPN's 47 tennis analysts, explained to the SportsCenter audience that Nadal plays tennis like an NFL running back. Like a Spanish Reggie Bush. A Majorcan Rashard Mendenhall. (Don't take Nadal early in your fantasy football draft, is what we're saying.)

"Rafael Nadal will never win another U.S. Open," I predicted in 2010, after Rafa had completed his career Grand Slam, beating Novak Djokovic and anointing Lil Wayne a tennis guru in the process. "With the U.S. Open securely in his pocket, Nadal now has nothing to prove in Flushing."

So who does Nadal's absence help the most? Perhaps Roger Federer, but he looks so annoyingly content with his Net Jet-commercial life at the moment, draws don't seem to matter.

Perhaps Djokovic, but after a loss to Federer in the Cincinnati final last week, the stringy Serb admitted he was mentally exhausted a year removed from his historic 2011 season, when he lost just six matches en route to winning the Australian Open, Wimbledon, and U.S. Open.

No, Nadal's geriatric knee opens the door for Andy Murray, who slayed at least one of his lingering inner demons by beating Federer in a final at the All England Club. Slight problem: It was at the Olympics, not Wimbledon.

Murray, who said he dreamed he won Wimbledon the night after his tear-inducing loss to Federer, has still never won a Grand Slam. The 2012 U.S. Open could be his best chance yet.

2. Serena Williams does the Crip Walk during her gold medal celebration after destroying Maria Sharapova at the London Olympics.

"I didn't know what else to do," Williams told reporters after her match, which she won, 6-0, 6-1. "I was so happy and next thing I know I started dancing and moving. I didn't plan it. It just happened."

Of course she didn't plan it. What she also didn't plan was to follow up her Wimbledon title and a quickie in Stanford with an Olympic title at Wimbledon—one in doubles too—that showed the rest of the tennis world that when she's on her game, she is maybe the greatest of all-time.

Remember when Serena Williams went all Joe Pesci on a line referee at the US Open two years ago?…
Read more Read more

"I'm thinking, already, something's gonna happen this year at the Open," Williams told The New York Times Magazine. "I'm just thinking, Serena, say your prayers, fall on your knees. It's frustrating, because it's my home country, you're playing for the home, but it's like, the way the umpires have been makes me not want to play there. I'd rather play in Australia, or I'd rather play at Wimbledon."

Lois Goodman is a 70-year-old tennis official. Earlier today, she was getting set to officiate U.S. …
Read more Read more

3. Sharapova launches Sugarpova. After her heartbreaking, near-double-bagel Olympic loss to Serena, the Russian national (by way of Bradenton) did what most tennis players who suffer disappointing losses do: she withdrew from tournaments, in Montreal and Cincinnati, opting instead to focus her public energy on the relatively high-profile launch of a line of candy called Sugarpova.

For Sharapova fans who've long argued that what separates her from the Kournikovas (and even Williamses) of the world is her tennis-first attitude, Sugarpova sucked. The Aug. 20 launch party at Henri Bendel on Fifth Avenue was sweet enough. But Sharapova has played more hard-candy events than hard courts this summer, which doesn't bode well for her winning a second U.S. Open title—especially if Serena is more locked in than ever, as she appears to be. (Blame Max Eisenbud, Sharapova's agent, who gave a rare interview to the Times because he said he wanted to draw attention to the "colorful line of lip-shaped gummies and tennis-ball shaped gum.")

Perhaps the loss in London left enough of a sour taste in Sharapova's mouth that she'll grind her way to the finals, where she'd more than likely meet Serena—which would be appropriately sticky. Crip walks all around.

Some other storylines to follow during the funky Flushing fortnight:

Is this the last gasp for aging American men like James Blake, Mardy Fish, and Andy Roddick?

For Fish, who rekindled his ranking with a manorexic's diet and P90X-like workout regiment, it's probably not. But a heart scare, like the one Fish experienced earlier this year, would make any athlete reassess his priorities.

For Roddick, who will celebrate his 30th birthday at the U.S. Open if he makes it to Thursday, it could be. The Austin statesman has struggled with the speculation that arrives in a career's twilight.

"If I win one, it's like career appreciation day," Roddick said after a 6-2, 6-1 loss to Djokovic at the Olympics. "If I lose one, it's like ‘We should take him out in the field and shoot him in the head.'"

For Blake, who has struggled with Nadal-like knee issues, it probably is.

Are any of the up-and-coming American women ready to make the second week?

Chances are, one of them is. Both Sloane Stephens, 19, and Christina McHale, everybody's neighbor's daughter, from Englewood Cliffs, N.J., made the third round of the Open last year. And Melanie Oudin, who rocketed to overnight stardom as a 17-year-old at the 2009 U.S. Open, has been more or less living at the Billie Jean King National Tennis Center constructing her comeback. McHale, 20, has been training here, too.